Endoscopy of the upper gastrointestinal tract typically involves passing one or more medical instruments through the alimentary canal. For example, endoscopes having different sizes may be sequentially intubated through the upper alimentary canal which includes the mouth, pharynx, esophagus, stomach and upper small intestine. Furthermore, prior to endoscopy, it is often necessary to evacuate the stomach of contents such as blood with an evacuation tube such as a lavage tube.
During conventional intubation such as endoscopy or evacuation of the upper alimentary canal, medical instrumentation is advanced from the patient's mouth into the patient's upper pharynx. Each time a medical instrument is advanced from the patient's mouth into the patient's pharynx, the medical instrument contacts the posterior wall of the pharynx, commonly known in the art as the "gag zone". This contact is typically unavoidable because the cavity of the mouth and the cavity of the pharynx are aligned at approximately right angles to one another, thereby forcing the medical instrumentation to be advanced through a tight curve. When medical instrumentation contacts the posterior wall of the pharynx, the gag zone is irritated, typically stimulating a gag reflex in the patient.
Gag reflexes are undesirable as the patient commonly experiences physical discomfort, may suffer respiratory damage or pneumonia due to the aspiration of blood and digestive fluids, may suffer damage to the alimentary canal as a result of the medical instrumentation moving therein, and may cause the medical instrumentation within the alimentary canal to move, thereby interfering with the successful completion of the medical procedure.
Conventionally, gag reflexes during intubation of the alimentary canal have been prevented by the combination of intravenous sedation prior to intubation along with the application of local anesthetics directly to the alimentary canal. The local anesthetics are applied to the alimentary canal as either throat sprays or as coatings applied to the medical instrumentation. The above-described combination numbs and relaxes the pharynx of the patient, thereby preventing a gag reflex.
A major draw back to the conventional method of endoscopy is that patients may react negatively to the intravenous sedatives. These reactions to the intravenous sedatives can vary greatly from patient to patient. Common reactions to intravenous sedatives include respiratory failure and heart rhythm disturbances. Additionally, a sedated patient is much more likely to aspirate blood or other stomach contents. Furthermore, the use of intravenous sedatives significantly increases post endoscopy recovery times, thereby increasing the cost of the procedure.